1,720,973 research outputs found
Effects of the purified IGF-I complex on the capacitation and acrosome reaction of rabbit spermatozoa
No full textA protein complex containing IGF-I, purified from rabbit seminal plasma, was used to investigate its effects on the capacitation and acrosome reaction of rabbit spermatozoa. Uncapacitated sperm (Pattern F), capacitated sperm (Pattern B), and acrosome-reacted sperm (Pattern AR) were determined by CTC staining, and the results were validated by PSA-staining. The addition of the IGF-I complex to the capacitative medium directed the spermatozoa to spontaneous acrosome reaction. On the other hand, IGF-I complex, added to capacitated spermatozoa, acted as inducer of the acrosome reaction. Results of IVF experiments showed high rates of fertilization with capacitated spermatozoa, acrosome-reacted by either A23187 or IGF I complex, whereas significantly lower rates were obtained with spermatozoa capacitated in the presence of IGF-I complex. © 2001 Wiley-Liss, Inc
Comparison of different dietary sources of PUFA n-3 on semen characteristics of rabbit bucks
No full textEffect of supranutritional level of dietary alpha-tocopheryl acetate and selenium on rabbit semen
No full textThis research examined the effects of dietary α-tocopheryl acetate (50 or 200 mg/kg diet) and selenium (Se, 0 or 0.5 ppm) supplementation on motion characteristics, oxidative stability and fertilizing ability of rabbit spermatozoa, fresh and stored for 24 h at 5°C. The higher amount of dietary α-tocopheryl acetate increased the level of Vitamin E in the fresh semen (1.75 mmol/l versus 0.95 mmol/l) and its oxidative stability (thiobarbituric acid reactive substances - TBARS 12.44 nmol malondialdehyde/108 sperm versus 21.4 nmol malondialdehyde/108 sperm). Dietary Se increased gluthatione peroxidase activity (GPx) in erythrocytes (285 U/g Hb versus 207 U/g Hb), seminal plasma (270 U/l versus 190 U/l) and spermatozoa (1338 mU/109 sperm versus 1103 mU/109 sperm), whereas it did not show any effect on α-tocopherol level and TBARS. No synergy between Vitamin E and Se was shown. Storage for 24 h at 5°C increased the TBARS level in all the experimental groups. Neither live and acrosome reacted spermatozoa, nor kinetic parameters, nor fertility rate were modified by dietary supplementation
Effect of PM10 on human spermatozoa:an in vitro study
No full textThis study was aimed at evaluating the in vitro effects of particulate matter (ranging from 2.5-10 μm in an aerodynamic diameter, PM10) from an urban area on the motility of human spermatozoa. Samples of swim up selected human spermatozoa from three healthy men with normal semen parameters, according to WHO guidelines, were incubated for 4 hours with 10, 50 and 75 μg/ml of PM10. Kinetic parameters were evaluated with Computer-Assisted Sperm Analysis (CASA) and the presence of apoptosis and necrosis was assessed by AnnexinV/Propidium iodide assay. Data was statistically elaborated. Incubation of sperm with 10 μg/ml PM10 for 4 hours did not affect sperm motility. On the contrary, a decrease in progressive motility was evident at 50 μg/ml and 75 μg/ml PM10. Among the kinetic parameters assessed with CASA system, the linearity variable was significantly lower in sperm treated with 50 μg/ml and 75 μg/ml PM10 vs controls (P<0.0001) and the amplitude of the lateral head displacement variable was significantly higher in sperm treated with 50 μg/ml vs controls (P=0.0211). A substantial increase in necrosis, in up to 30% of sperm, was evident only in samples treated with 75 μg/ml PM10. In conclusion, this preliminary study could indicate that PM10 is not potentially harmful to spermatozoa in vitro, except above a very high threshold (50-75 μg/ml) that is difficult to reach in vivo and that motility and viability are only partially affected. © Geminiani et al.; Licensee Bentham Open
Validation of a spectrophotometric method used for the measurement of spermatozoa and particles concentration in rabbit semen
No full textEFFECT OF DIETARY SUPPLEMENTATION WITH a-TOCOPHERYL ACETATE AND ASCORBIC ACID ON QUALITATIVE CHARACTERISTICS AND FERTILIZING ABILITY OF RABBIT SEMEN
No full text[EN] The aim of the present work was to verify the effect of atocopheryl
acetate addition - 50 vs 200 mg kg-1
- and ascorbic acid - O
vs 1 mg L-1
- on the characteristics of rabbit semen and its fertilizing
ability. The single supplementation of vitamin E and C, compared to the
control diet, did not modify semen traits, while the association of E+C significantly improved the kinetics of spermatozoa (60.73 vs 57.09 μm
sec-1
- path velocity) but without any effect on the fertility rate (70.00 vs
70.66 %). The results confirm that the standard recommendations far
vitamin E and C are adequate if fresh semen is used.[FR] Le but de ce travail est de vérifier l'effet de l'addition d'acétate d'atocopherol
dans l'aliment - 50 vs 200 mg/kg-1
- et de l'acide ascorbique
dans l'eau de boisson - O vs 1 mgr1
- sur les caractéristiques du
sperme de lapin et son pouvoir fertilisant. Comparée au régime témoin, la supplémentation par les vitamines E et C seules, ne modifie pas les
caractéristiques du sperme, tandis que l'association E+C augmente
significativement la cinétique des spermatozoides (60,73 vs 57,09 μm
sec-1
- vitesse d'acheminement) sans aucun effet sur le taux de feritlité
(70,00 vs 70,66 %). Ces résultats confirmen! que les recommandations
habituelles pour les vitamines E et C sont adéquates lorsque la
semence est utilisée fraiche.Castellini, C.; Lattaioli, P.; Bernardini, M. (1999). EFFECT OF DIETARY SUPPLEMENTATION WITH a-TOCOPHERYL ACETATE AND ASCORBIC ACID ON QUALITATIVE CHARACTERISTICS AND FERTILIZING ABILITY OF RABBIT SEMEN. World Rabbit Science. 07(4). https://doi.org/10.4995/wrs.1999.404SWORD07
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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